The invention relates to improvements in machines for making hot beverages, especially tea. More particularly, the invention relates to improvements in machines of the type wherein the housing supports or includes a pressure-resistant container for a supply of liquid to be heated (i.e., water if the machine is a tea maker), wherein an electric heater is located in the region of the lower part of the container to heat the supply of liquid therein, wherein the means for conveying heated liquid from the container into a steeping receptacle can include a riser which dips into the container and can discharge a stream of heated liquid into the receptacle wherein the heated liquid contacts a supply of flavoring agent (such as tea leaves), and wherein the receptacle has a sealable outlet which serves to dispense hot beverage into a cup, into a teapot, into a teakettle or into any other suitable vessel serving to confine a supply of hot beverage.
An appliance of the above outlined character is disclosed in German Offenlegungsschrift No. 2 428 165. This appliance can serve as a coffee or tea making machine, and the heater for the supply of liquid is installed directly in the interior of the container for the liquid. The container is designed to resist pressures which develop as a result of heating the liquid therein and is disposed at a level below a steeping receptacle which is adequately sealed to prevent the escape of aroma. The receptacle has a first chamber for heated water and a second chamber for a supply of comminuted coffee beans or tea leaves. The bottom wall of the first chamber carries a solenoid-operated valve which at first prevents the escape of hot beverage from the receptacle. A riser is provided to convey heated water from the container into the receptacle. The lower end of the riser serves to receive heated water and is located close to the bottom wall of the container, i.e., close to the electric resistance heater in the container. The riser extends through the bottom wall of the receptacle (this receptacle can constitute a portion of or the entire cover for the container), and the upper end of the riser is located in the interior of the receptacle, namely close to the removable cover of the receptacle. The electric heater is designed to boil water in the container so that the pressure in the container rises and boiling water flows upwardly into and through the riser to contact the supply of flavoring agent in the receptacle. The operator can select the duration of the interval of contact between water and the flavoring agent in the receptacle. To this end, the machine is equipped with a clock which can open the solenoid-operated valve after a selected interval of time so that the beverage can flow into a suitable vessel which is placed below the bottom wall of the receptacle.
A drawback of the just described machine is that it must employ a very long riser which extends from the bottom wall of the container for the supply of liquid and all the way to the cover of the steeping receptacle. The riser is permanently secured to the top wall of the container, i.e., to the bottom portion of the receptacle if such bottom portion is the top wall of the container. Thus, the operator is not in a position to shift the riser longitudinally and to thereby select the quantity of liquid which can remain in the lower portion of the container.
Another drawback of the aforediscussed machine is that the conventional electric resistance heater is installed in the interior of the container. This might contribute somewhat to compactness of the machine but presents serious problems as concerns the sealing of current-conducting parts of the heater from water in the interior of the container.
German Pat. No. 686 482 discloses a different machine for the making of tea or coffee. The patented machine employs three vessels which are located one above the other. The uppermost vessel is a container which serves to receive a supply of liquid to be heated and is provided with an external heating strap. The bottom wall of the container is provided with a valve which serves to discharge hot water into a second vessel below the container, namely a steeping receptacle with a filter which can be sealed by a valve. The lowermost vessel serves to receive hot beverage from the receptacle and can be provided with means for facilitating dispensing of hot beverage into cups, bowls or the like. A drawback of the patented machine is its pronounced height. Moreover, each of the two upper vessels must be provided with a discrete valve which contributes to the initial cost. Additional costs arise if the valves are controlled by clocks or by other auxiliary equipment. Still further, the efficiency of the patented machine is unsatisfactory because the aforementioned heating strap is located externally of the container for the supply of liquid to be heated so that only a small percentage of heat which is generated by such heater is actually used to raise the temperature of the liquid in the container.
German Pat. No. 3 312 354 discloses a machine with three superimposed vessels which constitutes an improvement over the machine of German Pat. No. 686 482 and is designed to make hot tea. One of the three vessels in the machine of German Pat. No. 3 312 354 is a container which serves to receive a supply of water and is provided with a heater, with a cover and with a sealable device which conveys hot water into a steeping receptacle. The outlet of the steeping receptacle is disposed above and can admit hot beverage into the third vessel. The sealable water conveying device is a riser which acts as a siphon, and the outlet of the steeping receptacle is controlled by a clock so that it can discharge fresh beverage after elapse of a selected interval of time. The machine of this German patent also exhibits several drawbacks, especially as regards its overall height (the three vessels are disposed one above the other). Moreover, the controls (normally electronic controls) are expensive, and the heating action of the conventional resistance heater is not overly satisfactory.